1. Field of the Invention
The invention relates generally to multi-layer electronic device packages, and more particularly, to routing signal traces in a multi-layer package.
2. Description of Related Art
Multi-layer electronic device packages, such as multi-layer printed circuit boards ("PCBs") and multi-chip modules ("MCMs"), are well known in the art. Multi-layer packages include a plurality of substrate layers, with at least one of the outer substrate layers of the multi-layer package typically adapted to have electronic components mounted thereon. One or more of the substrate layers has conductive traces incorporated therewith that act as wires to interconnect the components mounted on the package. Other layers may provide power and ground connections to the components.
Incorporating conductive traces in multiple substrate layers allows circuit designers to lay out complex circuit designs using numerous interconnections between components, while minimizing the required surface area of the package. Electrical connections between the various substrate layers of the package, and between layers of the package and components mounted on the package, is achieved using "vias." Basically, a via is a hole extending through substrate layers that is filled with conductive material to form an electrical connection.
Multi-layer packages are used extensively in computer systems and other semiconductor applications. The conductive traces of the multi-layer package may be used to route signals between components coupled to the package. Routing a high number of signals in a small area--especially high-speed signals--creates problems with parasitic noise generated from the signals routed through adjacent traces. This is especially problematic when multiple signal layers are employed for routing signals. This parasitic noise, sometimes also called "cross-talk," may result in spurious logic errors.
The present invention addresses some of the above mentioned and other problems of the prior art.